400721663 has 8 divisors (see below), whose sum is σ = 418563936. Its totient is φ = 382914400.

The previous prime is 400721611. The next prime is 400721683. The reversal of 400721663 is 366127004.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 400721663 - 2⁶ = 400721599 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (400721683) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16193 + ... + 32613.

It is an arithmetic number, because the mean of its divisors is an integer number (52320492).

Almost surely, 2^400721663 is an apocalyptic number.

400721663 is a deficient number, since it is larger than the sum of its proper divisors (17842273).

400721663 is a wasteful number, since it uses less digits than its factorization.

400721663 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17505.

The product of its (nonzero) digits is 6048, while the sum is 29.

The square root of 400721663 is about 20018.0334448717. The cubic root of 400721663 is about 737.2491383884.

Adding to 400721663 its reverse (366127004), we get a palindrome (766848667).

The spelling of 400721663 in words is "four hundred million, seven hundred twenty-one thousand, six hundred sixty-three".